1. Field of the Invention
The present invention relates in general to a boot method for systems. In particular, the present invention relates to a boot method for a system whose system BIOS has been disabled by erroneous microcode input as the result of inadvertent miscoding or malicious intent.
2. Description of the Related Art
In the environment of the present-day microprocessor industry, life cycles of CPU products are dramatically shortened; CPU retailers, in order to react to short RandD cycles, publish CPU products first to reach the market, then update microcode to system manufacturers later. The microcode is rectified when posting BIOS systems to ensure the liability of the CPU products. Additionally, most CPU retailers require system manufacturers to provide an interface in the BIOS system, so after purchasing, users can enter the microcode provided by the CPU retailers into the BIOS system as needed. Thereby, each time the users start up, system BIOS updates the microcode to effect BIOS activation of the system, and posts the latest program edition into the system.
However, this method can easily be used by malicious parties as a way to damage systems. Although CPU retailers have adopted the checksum method to verify the microcode written in BIOS, the malicious parties can still fabricate the checksum codes or send virus messages to post the wrong microcode into the system, disabling the CPU.
An object of the present invention is to provide a novel boot method for a computer system. When a system BIOS code (or a microcode to be updated) in the system is damaged, the system is still able to complete BIOS activation procedure and perform the startup.
The keyboard BIOS is incorporated in the present invention. If the computer CPU crashes during the microcode update, the system records the event (setting a number of flags) and restarts the computer. The restarted system will not perform the update, but go straight to normal BIOS activation for the system, thus avoiding the crash problem. Users need only ask for the correct microcode from the CPU retailer to fix the errors in the BIOS.
To solve the described problems, the present invention provides a boot method for a system; the boot method allows the system to be rebooted in the event of erroneous microcode input; the boot method comprises the following steps: after activating the system, checks to determine the necessity for an update, and notification to the keyboard BIOS about the update; the keyboard BIOS waits for a first predetermined period after the update; if an updated signal is not received, the keyboard BIOS sets a fail flag, shuts down the system and, after a second predetermined period, reboots. If the fail flag has already been set during the previous boot, the system does not update the microcode after activation, and sets a non-update flag to allow the system to perform normal BIOS activation. If the non-update flag has already been set during the previous boot, the system starts the BIOS activation procedure after the computer is activated; otherwise, the system confirms whether the update should commence according to the fail flag settings.